This invention relates to a process for preparing polyester yarn capable of wicking away moisture from the body and making the wearer more comfortable by treating polyester fibers in the form of yarn to make the normally hydrophobic polyester fibers hydrophilic.
Traditionally piece dyed goods have been processed and treated in fabric form with finishes to render the polyester hydrophilic and this limits the styling possibilities to solid shades.
Various proposals have been made to impart hydrophilic properties to synthetic fibers, particularly nylon and polyester, in the piece goods or fabric form. For example, fleece type sweatshirt fabrics in the form of a composite textile fabric having a first layer of a polyester or nylon material rendered hydrophilic and a second layer or a moisture absorbent material such as nylon are disclosed in U.S. Pat. No. 5,312,667 to Lumb et al. After knitting the fabric, the nylon or polyester component of the two layer fabric is rendered hydrophilic by treating the fabric in a dye bath to which a low molecular weight polyester such as Milease T (I.C.I.), Scotchguard FC-226 (3-M) or Zelcon (DuPont) has been added. The nylon- or polyester-containing layer of the composite is treated and dyed in fabric form.
Colored polyester fibers having hydrophilic groups grafted onto them are described in JP-A (Kokai) 48-96828 (1973). Colored graft fibers, prepared from solution (pigment) dyed polyester fibers placed in a dyeing machine with a hydrophobic radical initiator, organic solvent and hydrophilic monomer to graft polymerize the hydrophilic monomer onto the surface of the polyester fibers. The resultant product is said to have antistatic, moisture absorption, water absorption, soil resistance and thermal stability properties. This procedure requires the use of organic solvents insoluble in water, initiators and monitors, etc. all maintained under graft polymerization temperature and pressure conditions to fundamentally alter the characteristics of the polyester fibers, conditions not particularly convenient to conventional polyester yarn dyeing and processing.
It would be advantageous to include within the usual polyester dyeing process a treatment to render the normally hydrophobic polyester fibers hydrophilic and, in particular, to include this treatment in an otherwise conventional package dyeing operation. The resulting yarns may be knitted into either solids or styles such as jacquards, scoured and heatset without reducing the hydrophilic properties imparted concurrently during the dyeing operation.